JP2022114198A - Spring spacer, reinforcement cage, and underground pile installation method - Google Patents

Abstract

To provide a spring spacer capable of more accurately executing the positioning of a pile of a pile reinforcement cage in a radial direction and holding it, and preventing misalignment of a pile core of an underground pile, a reinforcement cage, and an underground pile installation method.SOLUTION: A spring spacer reinforcement 2 assembled to a reinforcement cage 1 built into an underground pile installed in the foundation comprises: an expansion part 23 that expands from a fastened part 24 with a main reinforcement 11 in the radial direction of the underground pile; and a bent part 22 bent and connected to the expansion part 23. The bent part 22 is bent so as to be parallel to the main reinforcement 11, and its free end 21 side is bent in the center direction of the underground pile.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a spring spacer for suspending and arranging a reinforcing bar cage in a pile hole, a reinforcing bar cage, and an underground pile driving method.

As a construction method for erecting piles in the ground, there are cast-in-place concrete piles in which a predetermined place is excavated and a reinforcing bar cage is erected in it and then concrete is poured in, and prefabricated reinforced concrete piles in which prefabricated reinforced concrete piles are driven (or embedded). be. The Building Standards Law stipulates that foundation piles such as cast-in-place concrete piles, raft foundations, and continuous foundations should be selected according to the soil bearing capacity of the site (the strength of the ground that continues to support the load of the building).

In the construction of the above-mentioned cast-in-place piles, casings such as steel pipe piles and pile reinforcing bar cages to be erected in pile holes drilled in the ground require installation accuracy in the depth direction and in the radial direction of the piles. As a method for ensuring installation accuracy in the depth direction in construction of this cast-in-place pile, for example, a construction method disclosed in Patent Document 1 is known. In the construction method disclosed in this Patent Document 1, a steel pipe having an anchoring bar is suspended by a wire and lowered to a predetermined position in a casing buried vertically in the ground. A threaded reinforcing bar is passed through a threaded member locked on a receiving base attached to the upper edge and temporarily fixed so as to be rotatable. By rotating the threaded reinforcing bar, the depth of the steel pipe is finely adjusted.

JP-A-06-167018

By the way, the position of the pile reinforcing bar cage in the pile radial direction is required to be accurate because it determines the rising position of the anchoring bar on the upper part of the pile reinforcing bar cage. On the other hand, in the upper part of the pile, the anchoring reinforcement of the upper part of the pile rebar cage, the foundation slab, the underground beam, the reinforcement of the column, etc. intersect and the reinforcement arrangement becomes complicated. Also, the diameter of the rebar used is large. For this reason, it is required that anchoring bars such as pile reinforcing bar cages do not interfere with reinforcing bars such as foundation slabs and underground beams.

However, in the construction method disclosed in Patent Document 1, there is no means for adjusting the position of the pile reinforcing bar cage in the pile radial direction and ensuring the position accuracy, so the positional accuracy of the anchoring bar of the pile reinforcing bar cage is constant. There was a risk that the pile core of the underground pile that was driven would be misaligned.

Therefore, the present invention has been made in view of the above-described problems of the prior art. To provide a construction method for installing a spring spacer, a reinforcing bar cage and an underground pile that can be installed.

In order to solve the above-mentioned problems, the present invention provides a spring spacer to be assembled in a reinforcing bar cage erected in an underground pile driven into the ground, wherein the spring spacer is installed in a radial direction of the underground pile from a connection portion with the main reinforcement. and a bent portion bent and connected to the expanded portion.

According to the present invention, the spring spacer bar is attached to the reinforcing bar cage. and a bent portion bent and connected to the portion. The expanded portion of the spring spacer bar contacts the hole wall so as to follow the resilience of the reinforcing bar, and the reaction force from the hole wall can be obtained to position the reinforcing bar cage in the center of the pile hole. In addition, since the widened portion has a bent portion in which the tip side thereof is bent, the spring spacer bar does not get caught on the hole wall, the casing, etc., and the smooth sinking of the reinforcing bar cage is not hindered.

In the above invention, the bent portion is preferably bent so as to be parallel to the main reinforcement. In the above invention, it is preferable that the free end side of the bent portion is bent toward the center of the underground pile. In this case, the bent portion is bent so as to be parallel to the main reinforcement, and the free end side of the bent portion is bent toward the center of the underground pile, so that the spring spacer bar can be installed on the hole wall, casing, etc. It is possible to more reliably prevent the cage from being caught in the ditch, and it is possible to set the reinforcing bar cage smoothly.

Further, the present invention is a reinforcing bar cage erected in underground piles driven into the ground, wherein a plurality of main reinforcements arranged in parallel in the vertical direction are connected to the plurality of main reinforcements in the horizontal direction. It has a hoop bar and a spring spacer bar that is tightened and fixed to the main bar. and a bent portion that is connected while being bent.

According to the present invention, the spring spacer bar is attached to the reinforcing bar cage. and a bent portion bent and connected to the portion. The expanded portion of the spring spacer bar contacts the hole wall so as to follow the resilience of the reinforcing bar, and the reaction force from the hole wall can be obtained to position the reinforcing bar cage in the center of the pile hole. In addition, since the widened portion has a bent portion in which the tip side thereof is bent, the spring spacer bar does not get caught on the hole wall, the casing, etc., and the smooth sinking of the reinforcing bar cage is not hindered.

In the above invention, the bent portion is preferably bent so as to be parallel to the main reinforcement. Moreover, in the above invention, it is preferable that the free end side of the bent portion is bent toward the center of the underground pile. In this case, the bent portion is bent so as to be parallel to the main reinforcement, and the free end side of the bent portion is bent toward the center of the underground pile, so that the spring spacer bar can be installed on the hole wall, casing, etc. It is possible to more reliably prevent the cage from being caught in the ditch, and it is possible to set the reinforcing bar cage smoothly.

In the above invention, an underground pile driving method using the spring spacer according to any one of claims 1 to 3, comprising a step of excavating a pile hole in the ground, and a reinforcing bar erected in the pile hole An underground pile driving method comprising the steps of assembling a spring spacer to a main reinforcement of a cage by tightening, and sinking a reinforcing bar cage into a pile hole.

According to the present invention, the spring spacer bar is attached to the reinforcing bar cage. and a bent portion bent and connected to the portion. The expanded portion of the spring spacer bar contacts the hole wall so as to follow the resilience of the reinforcing bar, and the reaction force from the hole wall can be obtained to position the reinforcing bar cage in the center of the pile hole. In addition, since the widened portion has a bent portion in which the tip side thereof is bent, the spring spacer bar does not get caught on the hole wall, the casing, etc., and the smooth sinking of the reinforcing bar cage is not hindered.

In the above invention, the step of excavating the pile hole includes the step of installing a casing covering the excavated wall surface near the ground surface opening of the pile hole, and the step of sinking the reinforcing bar cage, the spring spacer after sinking is attached to the casing It is preferable that the bent portion is in contact with the inner wall portion of the casing while being positioned at the depth of the portion covered with the .

In addition, if the spring spacer bars are positioned below the depth of the part covered with the casing after sinking, and the reinforcing bar cage is positioned in the depth direction so that the spring spacer bars do not overlap the casing, the piles will not reach the excavated wall surface. Preferably, the bend is brought into contact with the excavation wall surface by earth pressure toward the center of the ridge. At this time, while the earth pressure from the excavation wall surface is suppressed by the casing, the earth pressure is released when the casing is not present. The degree of opening is less than the degree of opening of the widened portion when the spring spacer bar crosses the casing.

As described above, in the present invention, the spring spacer bar is attached to the reinforcing bar cage. and a bent portion bent and connected to the portion. The expanded portion of the spring spacer bar contacts the hole wall so as to follow the resilience of the reinforcing bar, and the reaction force from the hole wall can be obtained to position the reinforcing bar cage in the center of the pile hole. In addition, since the widened portion has a bent portion in which the tip side thereof is bent, the spring spacer bar does not get caught on the hole wall, the casing, etc., and the smooth sinking of the reinforcing bar cage is not hindered. As a result, according to the present invention, it is possible to easily adjust and hold the radial position of the reinforcing bar cage, and to prevent the pile core of the placed underground pile from being displaced.

It is explanatory drawing which shows the procedure of the driving construction method of the underground pile which concerns on embodiment. FIG. 4 is a side view showing the appearance of the spring spacer according to the embodiment; It is a top view which shows the external appearance of the reinforcing bar cage which concerns on embodiment. It is a perspective view which shows the structure (state where the spring spacer is expanded) of the reinforcing-bar cage which concerns on embodiment. 1 is a perspective view showing a configuration of a reinforcing bar cage according to an embodiment (with spring spacers contracted); FIG. 1 is a cross-sectional view showing an underground pile driving method (with a casing) according to an embodiment; FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional perspective view which shows the driving method (with a casing) of the underground pile which concerns on embodiment. It is a cross-sectional view showing an underground pile driving method (without casing) according to the embodiment. BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional perspective view which shows the driving method (without casing) of the underground pile which concerns on embodiment.

DETAILED DESCRIPTION OF THE INVENTION Embodiments of a spring spacer, a reinforcing bar cage, and an underground pile driving method using these according to the present invention will be described below in detail with reference to the accompanying drawings. The embodiments shown below are examples of devices and the like for embodying the technical idea of this invention. It does not specify the layout, etc., to the following. The technical idea of this invention can be modified in various ways within the scope of claims.

(Overall configuration of construction equipment)
FIG. 1 is an explanatory diagram showing the procedure of the underground pile driving method according to the present embodiment. In this embodiment, a pile hole G2 is excavated in the ground G in order to build a pile foundation for supporting a building when building a new building or rebuilding. Specifically, as shown in FIG. 1, an arm 91 of the heavy machine 9 lifts a kelly bar 92 to suspend an earth drill 93 for excavation. Then, the earth drill 93 for excavation is lowered while being rotated in one direction by the Kelly bar 92 to be buried in the ground, and the pile hole G2 is excavated. The heavy machinery 9 also has crane equipment for lifting the casing 8 and the reinforcing bar cage 1 and sinking them into the pile hole G2.

(Configuration of Reinforcement Cage 1)
Next, the configuration of the reinforcing bar cage 1 will be described. 2 to 5 show the configuration of the reinforcing bar cage 1 according to this embodiment. As shown in the figure, the reinforcing bar cage 1 is a reinforcing bar cage erected in underground piles driven into the ground G. As shown in FIG. Specifically, the reinforcing bar cage 1 includes a plurality of main bars 11 arranged in parallel in the vertical direction, an annular hoop bar 12 connecting the main bars 11 in the horizontal direction, and a spring fixed by tightening the main bars 11. spacer bars 2;

A predetermined number of the main reinforcements 11 are arranged at predetermined intervals on the circumference, each of the main reinforcements 11 is arranged in parallel in the vertical direction, and the plurality of main reinforcements 11 form a cylindrical shape as a whole. Circular hoop reinforcements 12 are provided on the outer periphery of the main reinforcement 11 at predetermined intervals in the pile axis direction. The upper portion of the main reinforcement 11 serves as an anchoring reinforcement to the foundation, and protrudes above the hoop reinforcement 12 at the top. A steel ring-shaped reinforcing member or the like is provided inside the main reinforcing bars 11 to maintain the circular arrangement of the main reinforcing bars 11 . The reinforcing members are attached at appropriate intervals in the pile axis direction of the reinforcing bar cage 1 .

As shown in FIG. 2, the spring spacer bar 2 is fixed by being tied with a number wire 25 with the knotted portion 24 along the main reinforcement 11 of the reinforcing bar cage 1 . In this embodiment, the spring spacer bars 2 are formed of D25 reinforcing bars, and as shown in FIG.

Moreover, as shown in FIGS. 6 and 8, the spring spacer bar 2 is positioned below the top of the pile from the first hoop bar 12a positioned at the top of the reinforcing bar cage 1 (pile head position). are also located below. 6 shows a state in which the casing 8 is buried in the ground G and the spring spacer bars 2 are arranged within the embedding depth of the casing 8 (the depth of the portion covered with the casing). Although the state without 8 is shown, in any state, the spring spacer bar 2 is arranged below the first hoop bar 12a arranged at the top (pile head position) of the reinforcing bar cage 1. there is

As shown in detail in FIG. and a bent portion 22 connected while being bent. In this embodiment, a single reinforcing bar is radially bent from the binding portion 24 and expanded to form the expanded portion 23 , and the free end side of the expanded portion 23 is bent to form the bent portion 22 . The binding portion 24, the flared portion 23 and the bent portion 22 are integrally formed.

The binding portion 24 is laid along the main reinforcement 11 and arranged parallel to the main reinforcement 11 , and the expanding portion 23 is bent with respect to the binding portion 24 and directed outwardly of the binding portion 24 in a predetermined direction. It extends obliquely upward at an angle of . A bent portion 22 is formed on the free end side of the expanded portion 23 extending obliquely upward.

Furthermore, in the present embodiment, the bending portion 22 is bent from the binding portion 24 through the expanded portion 23 so as to be parallel to the binding portion 24 and the main reinforcement 11 . Further, the free end 21 side of this bent portion 22 is bent toward the center side of the underground pile.

As a result, the expanded portion 23 of the spring spacer bar 2 is expanded radially outward by the resilience of the reinforcing bar and comes into contact with the hole wall so as to follow it. A reaction force from the inner wall surface is obtained to position the reinforcing bar cage 1 at the center of the pile hole. At this time, since the widened portion 23 has a bent portion 22 in which the distal end side thereof is bent, the spring spacer bar 2 is not caught on the excavated wall surface G3, the casing 8, and the like.

6 and 7, the spring spacer bar 2 is located at the depth of the part covered with the casing 8 after sinking, and the spring spacer bar 2 When the reinforcing bar cage 1 is positioned in the depth direction so that the rebar cage 1 is placed on the casing 8 , the expanded portion 23 is expanded radially outward due to the resilience of the reinforcing bar, and the bent portion 22 is pushed by the casing 8 . The opening degree of the expanded portion 23 is adjusted so that it contacts the inner wall portion of the.

Moreover, as shown in FIGS. 8 and 9, the spring spacer bars 2 are positioned below the depth of the portion covered with the casing 8 after sinking, and the depth of the reinforcing bar cage 1 is adjusted so that the spring spacer bars 2 do not overlap with the casing 8 . The opening degree of the widened portion 23 is adjusted so that the bent portion 22 is brought into contact with the excavated wall surface G3 by the earth pressure from the excavated wall surface G3 toward the center of the pile when the vertical positioning is performed. In addition, while the earth pressure from the excavation wall surface G3 is suppressed by the casing 8, the earth pressure is released when the casing 8 is not present. The opening degree of the expanding portion 23 is smaller than the opening degree of the expanding portion 23 when the spring spacer bar 2 is in contact with the casing 8 .

On the other hand, the casing 8 is a hollow tubular steel member having a substantially circular cross section. The casing 8 has a length sufficient to protect the hole wall of the ground surface layer of the pile hole G2. In this casing 8, the spring spacer bar 2 is arranged below the first hoop bar 12a positioned at the highest position (pile head position) of the reinforcing bar cage 1 so that the spring spacer bar 2 is positioned below the top of the pile.

(In-ground pile driving method)
The underground pile driving method of the present invention can be carried out using the construction equipment and the reinforcing bar cage described above. 1 and 5 to 8 show the procedure of the underground pile driving method according to this embodiment.

First, a step of excavating a pile hole in the ground is performed. Specifically, as shown in FIG. 1A, an arm 91 of the heavy equipment 9 lifts a Kelly bar 92 to suspend an earth drill 93 for excavation. Then, the earth drill 93 for excavation is lowered while being rotated by the Kelly bar 92 to be embedded in the ground G, and the pile hole G2 is excavated. The excavation at this time is performed to a depth at which the casing 8 can be sunk.

After the pile hole G2 is excavated to a predetermined depth, a casing 8 covering the excavated wall surface G3 is set near the ground surface opening of the pile hole G2, as shown in FIG. This sinking of the casing 8 is performed by lifting the casing 8 using the crane equipment of the heavy machine 9 . When sinking, the casing 8 is inserted into the ground G so that the upper end of the casing 8 appears on the ground. Then, as shown in FIG. 4C, the pile hole bottom surface G1 in the casing 8 is excavated to a predetermined depth deeper than the insertion depth of the casing 8. Then, as shown in FIG.

Then, as shown in FIG. 1(d), a step of sinking the reinforcing bar cage 1 into the pile hole is performed. Prior to this sinking, a step of assembling the spring spacer bars 2 to the main bars 11 of the reinforcing bar cage 1 by tightening with wire 25 is performed. More specifically, the main reinforcements 11 are arranged in a predetermined number on the circumference at predetermined intervals. Each of the main reinforcements 11 is arranged in parallel in the vertical direction. The reinforcing bars are arranged at predetermined intervals in the direction, and the reinforcing bar cage 1 is formed in a cylindrical shape as a whole. As shown in FIG. 2, the spring spacer bar 2 is fixed by being tied with wire 25 in a state in which the binding portion 24 is aligned with the main reinforcing bar 11 of the casing 8 .

In this embodiment, the spring spacer bars 2 are radially expanded from the center of the pile on the outer periphery of the cylindrically arranged main bars 11 as shown in FIG. In this embodiment, four spring spacer bars 2 are arranged at 90 degrees each at the central angle of the pile.

In the process of sinking the reinforcing bar cage 1, as shown in FIGS. 1 depth positioning is performed. At this time, the opening degree of the expanded portion 23 is adjusted so that the bent portion 22 contacts the inner wall portion of the casing 8 . As shown in FIGS. 8 and 9, the spring spacer bars 2 are positioned below the depth of the portion covered with the casing 8 after sinking, and the depth of the reinforcing bar cage 1 is set so that the spring spacer bars 2 do not overlap the casing 8. When positioning in the vertical direction is achieved, the bent portion 22 is brought into contact with the excavated wall surface G3 by earth pressure from the excavated wall surface G3 toward the center of the pile. At this time, the earth pressure from the excavation wall surface G3 is suppressed by the casing 8, and the earth pressure is released when the casing 8 is not present, so the spring spacer bars 2 are not applied to the casing 8. , the opening degree of the expanding portion 23 is smaller than the opening degree of the expanding portion 23 when the spring spacer bar 2 touches the casing 8 .

Next, a step of placing concrete in the pile hole G2 is performed. Specifically, as shown in FIG. 1(e), the tremie pipe 94 is inserted through the interior of the sunken reinforcing bar cage 1 so as to reach the pile hole bottom surface G1. After that, as shown in FIG. 1(f), concrete 3 is filled. At this time, the concrete 3 is filled up to the upper side of the first hoop reinforcement 12a so that the first hoop reinforcement 12a is positioned below the top of the pile.

After that, when the casting of the concrete 3 is completed, the casing 8 is pulled out from the ground G, and the pile driving work is completed. Even when the casing 8 is pulled out from the ground G, the spring spacer bar 2 is positioned below the top of the pile as shown in FIGS. position) below the first hoop muscle 12a. As a result, even if the casing 8 is pulled out before the concrete hardens and the surrounding excavated wall surface G3 is displaced, it is possible to prevent the pile core of the placed underground pile from being displaced. Further, the part of the ground G where the casing 8 has been pulled out is filled with backfill soil.

(action/effect)
According to the present embodiment described above, the spring spacer bar 2 is attached to the reinforcing bar cage 1, and the spring spacer bar 2 expands from the connection portion 24 with the main bar 11 in the radial direction of the underground pile. It has an opening 23 and a bent portion 22 bent and connected to the expanded portion 23 . The expanded portion 23 of the spring spacer bar 2 contacts the hole wall so as to follow it due to the resilience of the reinforcing bar, and receives the reaction force from the excavation wall surface (hole wall) G3 to move the reinforcing bar cage 1 to the center of the pile hole. can be positioned.

In addition, since the widened portion 23 has a bent portion 22 in which the distal end side is bent, the spring spacer bar 2 does not get caught on the excavated wall surface G3, the casing 8, etc., and smooth sinking of the reinforcing bar cage 1 is prevented. never. As a result, according to this embodiment, the radial position of the reinforcing bar cage 1 can be easily adjusted and held, and the pile core of the placed underground pile can be prevented from being displaced.

In particular, in this embodiment, the bent portion 22 is bent parallel to the main reinforcement 11, and the free end 21 side of the bent portion 22 is bent toward the center of the underground pile. can be more reliably prevented from being caught on the excavated wall surface G3, the casing 8, etc., and the sinking of the reinforcing bar cage 1 can be performed smoothly.

Note that the above description of the embodiment is an example of the present invention. Therefore, the present invention is not limited to the above-described embodiments, and various modifications can be made according to design and the like without departing from the technical idea of the present invention.

G... Ground G1... Bottom of pile hole G2... Pile hole G3... Excavation wall surface 1... Reinforcing bar cage 2... Spring spacer bar 3... Concrete 8... Casing 9... Heavy machine 11... Main bar 12... Hoop bar 21... Free end 22... Bending part 23 ... Expansion part 24 ... Tightening part 25 ... Wire 91 ... Arm 92 ... Kelly bar 93 ... Earth drill for excavation 94 ... Tremy tube

In order to solve the above-mentioned problems, the present invention provides a spring spacer to be assembled in a reinforcing bar cage erected in an underground pile that is driven into the ground, wherein the spring spacer is tightened along the main bars of the reinforcing bar cage. a binding portion that is fixed by the binding portion, a widening portion that is bent and expanded in the radial direction of the underground pile from the binding portion, and a bent portion that is bent and connected to the expanded portion, and the bending The free end side of the portion is bent toward the center of the underground pile, and the binding portion, the expanded portion and the bent portion are integrally formed by bending a single reinforcing bar .

According to the present invention, the spring spacer bar is attached to the reinforcing bar cage. and a bent portion bent and connected to the portion. The expanded portion of the spring spacer bar contacts the hole wall so as to follow the resilience of the reinforcing bar, and the reaction force from the hole wall can be obtained to position the reinforcing bar cage in the center of the pile hole. In addition, since the widened portion has a bent portion in which the tip side thereof is bent, the spring spacer bar does not get caught on the hole wall, the casing, etc., and the smooth sinking of the reinforcing bar cage is not hindered. In addition, since the free end side of the bent portion is bent toward the center of the underground pile, it is possible to more reliably prevent the spring spacer bar from being caught in the hole wall, casing, etc., and to facilitate the sinking of the reinforcing bar cage. It becomes possible.

In the above invention, it is preferable that the spring spacer is radially expanded from the center of the underground pile on the outer periphery of the main reinforcement, and the tightening portion is arranged along the main reinforcement so as to extend along the main reinforcement. The expanded portion is bent with respect to the binding portion and extends obliquely upward toward the outside of the binding portion at a predetermined angle, and the bent portion is oblique It is preferably formed on the free end side of the expanded portion extending upward. Moreover, in the above invention, it is preferable that the bent portion is bent so as to be parallel to the main reinforcement .

Further, the present invention is a reinforcing bar cage erected in underground piles driven into the ground, wherein a plurality of main reinforcements arranged in parallel in the vertical direction are connected to the plurality of main reinforcements in the horizontal direction. The spring spacer bar includes a hoop bar and a spring spacer bar that is tied and fixed to the main bar. It has an expanded portion that is bent and expanded in the radial direction of the underground pile, and a bent portion that is connected to the expanded portion while being bent, and the free end side of the bent portion is the center of the underground pile. The binding portion, the expanding portion and the bending portion are integrally formed by bending a single reinforcing bar .

According to the present invention, the spring spacer bar is attached to the reinforcing bar cage. and a bent portion bent and connected to the portion. The expanded portion of the spring spacer bar contacts the hole wall so as to follow the resilience of the reinforcing bar, and the reaction force from the hole wall can be obtained to position the reinforcing bar cage in the center of the pile hole. In addition, since the widened portion has a bent portion in which the tip side thereof is bent, the spring spacer bar does not get caught on the hole wall, the casing, etc., and the smooth sinking of the reinforcing bar cage is not hindered. In addition, since the free end side of the bent portion is bent toward the center of the underground pile, it is possible to more reliably prevent the spring spacer bar from being caught in the hole wall, casing, etc., and to facilitate the sinking of the reinforcing bar cage. It becomes possible.

In the above invention, it is preferable that the spring spacer is radially expanded from the center of the underground pile on the outer periphery of the main reinforcement, and the tightening portion is arranged along the main reinforcement so as to extend along the main reinforcement. The expanded portion is bent with respect to the binding portion and extends obliquely upward toward the outside of the binding portion at a predetermined angle, and the bent portion is oblique It is preferably formed on the free end side of the expanded portion extending upward. Moreover, in the above invention, the bent portion is preferably bent so as to be parallel to the main reinforcement .

In order to solve the above-mentioned problems, the present invention provides a spring spacer to be assembled in a reinforcing bar cage erected in an underground pile that is driven into the ground, wherein the spring spacer is tightened along the main bars of the reinforcing bar cage. a binding portion that is fixed by the binding portion, a widening portion that is bent and expanded in the radial direction of the underground pile from the binding portion, and a bent portion that is bent and connected to the expanded portion, and the bending The section has a straight portion bent with respect to the expanded portion, and a free end side of the straight portion is further bent toward the center of the underground pile, and the binding portion, the expanded portion and the bent portion are It is formed integrally by bending a single reinforcing bar.

Further, the present invention is a reinforcing bar cage erected in underground piles driven into the ground, wherein a plurality of main reinforcements arranged in parallel in the vertical direction are connected to the plurality of main reinforcements in the horizontal direction. The spring spacer bar includes a hoop bar and a spring spacer bar that is tied and fixed to the main bar. An expansion portion that is bent and expanded in the radial direction of the underground pile, and a bending portion that is connected to the expansion portion while being bent, and the bending portion is bent with respect to the expansion portion. It has a bent straight portion , the free end side of the straight portion is further bent toward the center of the underground pile, and the binding portion, the expanded portion and the bent portion are integrally formed by bending a single reinforcing bar. is formed in

Claims (8)

A spring spacer assembled in a reinforcing bar cage erected in an underground pile driven into the ground,
an expanding portion that expands in the radial direction of the underground pile from the connection portion with the main reinforcement;
A spring spacer, comprising: a bent portion that is bent and connected to the expanded portion. 2. The spring spacer according to claim 1, wherein said bent portion is bent so as to be parallel to said main reinforcement. 2. The spring spacer according to claim 1, wherein the free end side of the bent portion is bent toward the center of the underground pile. A reinforcing bar cage erected in underground piles driven into the ground,
a plurality of main rebars arranged in parallel in the vertical direction;
a hoop reinforcement horizontally connecting the plurality of main reinforcements;
and a spring spacer muscle tightened and fixed to the main reinforcement,
The spring spacer bar is characterized by having an expanded portion that expands in a radial direction of the underground pile from a portion connected to the main reinforcing bar, and a bent portion that is bent and connected to the expanded portion. Reinforced cage. The reinforcing bar cage according to claim 4, wherein the bent portion is bent so as to be parallel to the main reinforcement. The reinforcing bar cage according to claim 4, wherein the free end side of the bent portion is bent toward the center of the underground pile. An underground pile driving method using the spring spacer according to any one of claims 1 to 3,
excavating a pile hole in the ground;
a step of assembling the spring spacer to the main reinforcement of the reinforcing bar cage erected in the pile hole by tightening;
a step of sinking the reinforcing bar cage in the pile hole;
and a step of placing concrete in the pile hole. The step of excavating the pile hole includes the step of installing a casing covering the excavated wall surface near the ground surface opening of the pile hole,
In the step of sinking the reinforcing bar cage, the spring spacer after sinking is positioned at the depth of the portion covered with the casing, and the bent portion is in contact with the inner wall portion of the casing. The underground pile driving method according to claim 7.

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